Lay-out jig



Patented Apr. 7, 1953 LAY-OUT J IG Harold v. May, Pittsfield, Mass.,assignor to Spraguc Electric Company, a corporation of MassachusettsApplication June 26, 1951, Serial No. 233,651

2 Claims.

This invention relates to new and improved precision lay-out jigs forthe formation of patterns from which screens used in stencilin ceramicdielectrics are manufactured.

A considerable problem has existed in the art of manufacturing suchpatterns because of the extreme accuracy required in the work. Errors ofas much as .001 of an inch in the size of the final pattern have causedpatterns to be rejected. The scope of this problem is more readily seenwhen it is realized that as many as 72 ceramic discs or plates arestenciled with molten silver through a screen measuring 3.500" x 3.200"in diameter. As long as 10 hours have frequently been required to form asatisfactory pattern from which a screen used in stenciling dielectricscould be produced. Men have not been able to work for long periodsproducing such patterns because of the eye strain caused by the smalldimensions involved.

It is an object of this invention to produce a jig from which thesepatterns can be easily laid out in a relatively short period. It is afurther object of this invention to produce a jig which can be used withthe production of patterns for stenciling any different number ofdielectric discs. Further objects become apparent from the annexedspecification and claims.

Referring specifically to the drawings, Figure 1 shows an isometric viewof the jig produced in accordance with this invention; and Figure 2shows a stylus used with this J'ig.

In Figure 1, l designates the jig body preferably formed of A2" sheetsteel having the sides ground smooth. Handles II are attached to the midsection of opposite sides of the jig in order to facilitate its removal.A rectangular center opening I2 is formed medially within the body andis bridged by a guide bar 9 fastened by appropriate pins 24 to opposed,parallel, aligned holes 16 in the base 10. The guide bar 8 is furnishedwith a series of openings l4 medially throughout its length. It will bereadily seen from the drawings that the bar 9 may be moved from locationto location across the opening l2 by pulling the pins 24, moving the barto the next set of holes [6 and then reinserting these pins.

The operation of the jig itself is quite simple. The jig body I0 isplaced over a plastic or paper sheet (not shown), so that a portion ofthe sheet which is to contain the pattern'is located within the opening12. The weight of the body I0 is sufficient to hold it in position. Thebar 9 is then placed in position as indicated across the opening. Astylus such as is shown in Figure 2 having a knurled handle 22, acentral round portion 2|, and a central pin point 23, is insertedthrough each of the holes [4 so as to make appropriate markings in theplastic or paper sheet by virtue of the pin point 23 engaging the sheet.The process is repeated with all the desirable positions of the bar 9and the holes 14, so as to produce a series of points on the plastic orpaper sheet from which individual ceramic patterns may be drawn.

A number of different sets of parallel, aligned holes besides thosedesignated as it may be formed on the jig body I0. For convenience onlyone other series of holes I5 has been shown, but others may be used inconjunction with other bars (not shown) besides the bar 9 in order toproduce any desired combination of marking points with the jig. All ofthe surfaces which bear against one another in the jig are ground fiat.The openings l4 through which the stylus 20 projects are ground to aperfect fit with the cylindrical portion 2| of the stylus, so that thereis no possibility of marking other than one designated spot when usingthe marker. The holes 25 through which the pegs 24 project into openingsl5 and IS in the base III are similarly ground to a perfect fit.

Patterns used in the production of screens for stenciling ceramics madewith the described jig have an error of less than .0002 of an inch ascompared with errors of .001 of an inch as previously encountered withthis type of pattern. The time for laying out such patterns has beenreduced from approximately 10 hours to 5 minutes.

Those skilled in the art will realize that various modifications of theinvention besides those modifications indicated in the specification maybe made. For example, the parts may be made of other materials besidessteel. However, it is to be understood that the inventive conceptinvolved is to be measured only by the scope of the appended claims.

What is claimed is:

1. A precision layout jig for the production of patterns used formingscreens for the stenciling of ceramic plates which comprises, arectangular steel plate defining a rectangular opening formed mediallyof said plate, handles on opposed sides of said plate, means definingseries of parallel aligned openings on opposite edges of saidrectangular opening, a guide bar having means defining end openingsfastened to said plate across. said rectangular opening by pins extendinthrough said end openings into two of said aligned openings on oppositeedges of said rectangular opening, and means defining a series ofregularly spaced holes across the central portion of said bar.

2. A jig as defined in claim 1 in which said bar and said plate areground flat, and in which said aligned and end openings are ground tofit around said pins without noticeable play.

HAROLD V. MAY.

4 REFERENCES CITED UNITED STATES PATENTS Number Name Date Wait Jan. 19,1909

